IF MORAL clarity graced our times, the publication of Paul Hollander's comprehensive compilation of first-hand accounts by former communist victims, From the Gulag to the Killing Fields, would elicit a collective shudder of horror and sorrow.

"Systematic evil at work: evil without conscience." So does Harvard University professor Harvey Mansfield describe the grotesque crimes the selections illustrate. The book provides "an indispensable experience for the understanding of our times." No wonder it lingered in manuscript for several years: One publisher after another, simply reflecting readers' priorities, turned down the project until finally the Intercollegiate Studies Institute saved the day. Having failed to predict communism's collapse, our political experts now seem eager to forget about it altogether.

Indeed, as Hollander notes in his introduction, "it is difficult to identify a single American scholar specializing in Communist political violence, either as a comparative endeavor or as one focused on a particular Communist system." The incomparable Robert Conquest of the Hoover Institution, among the first to expose the enormity of Soviet crimes, was born in Great Britain, and Anne Applebaum, whose breathtaking 2005 work Gulag: A History earned her a Pulitzer Prize, is a journalist. Hollander, who taught sociology at the University of Massachusetts at Amherst, was born in Hungary, which he fled after the abortive revolution of 1956. His tome demonstrates that comparative communist political violence is a field eminently ripe for academic study. It is also an impressive tribute to the most horrific event of the last century apart from the Holocaust.

Communist crimes are less known than fascist ones. While newly released archives from the former Soviet bloc will unquestionably deepen our understanding of the Holocaust, we already have a plethora of photographic documentation, surviving physical evidence, magnificent museums and survivor testimony. By contrast, Soviet atrocities are practically ignored.

The reason is certainly not a paucity of information, as this massive work amply demonstrates. But what sets Hollander's anthology apart from other books is less its size than its astonishing breadth. Alongside victims from the Soviet Union are East Europeans-from Albania, Bulgaria, Czechoslovakia, East Germany, Hungary, Poland, Romania and Yugoslavia-as well as their counterparts from China, Cambodia, Vietnam and North Korea in Asia, Cuba and Nicaragua in Latin America, and Ethiopia. The geographic spread does not merely overwhelm the reader: Its principal purpose is analytical. As Anne Applebaum observes in her appreciative preface, at last now "it is truly possible to understand the cross-cultural, multinational history of communism as a single phenomenon." Readers can draw the lines of influence-ideological, financial and strategic-with greater precision than ever, "from Lenin to Stalin to Mao to Ho Chi Minh to Pol Pot, from Castro to the MPLA in Angola."

Communist terror varied from one country or region to another, and at different times within any one geographic unit; nevertheless, the common elements, both theoretical and practical, are easy to discern. Political police forces (known as "state security" organs), charged with controlling "ideological" rather than ordinary crime, tended to dehumanize the "class enemy" as historically obsolete and "destined" to become extinct. Abuse of the "mentally ill" designation also cut across communism's manifestations.

Marx and Engels' oxymoronic "dialectical materialism", juxtaposing the inevitability of revolution with the imperative of party leadership and predicated on a quasi-divine belief in history as progress, allowed zealous disciples to justify terror and murder by transforming "is" into "ought." Lenin understood perfectly that the next stage of history must be right, hence any means to bring it about were justified. Therefore, expediting the proletarian nirvana requires "eliminating" those who doubt the omnipotence, omniscience and benevolence of history's anointed force, the vanguard of the proletariat, the Communist Party.

Not unexpectedly, as nirvana became more elusive, the number of concentration camp inmates grew. Their crimes were often simply accusations-or having been arrested. As the gap between reality and promise increased, so did the need to eliminate those most likely to notice. Repressive measures, including imprisonment and torture, were most frequently taken not against declared ideological opponents, but against members of an inherently "counterrevolutionary class."

In my native Romania, for example, the construction site of the Danube-Black Sea Canal (aptly dubbed "The Channel of Death") became a graveyard for professionals, dispossessed farmers regardless of ethnicity, Romanian Orthodox priests, Zionists, Yugoslavs from the Banat region, Saxons from Transylvania and other "unfriendly" elements guilty of the wrong address, the wrong language or the wrong trade. Hollander observes that all communist states, across all continents, defined "collective responsibility" (euphemism for group guilt) as various common traits, like wearing glasses-presumably a sign of intellectualism, i.e., "bourgeois elitism." Canal victims were beaten "with iron bars, shovels, spades, and whips." In winter, "prisoners were put naked or skimpily dressed in isolation cells [and] . . . punished by making them stand in frozen water." With the seasons, the techniques changed but not the terror: "Prisoners were tied by the hands and exposed naked in the summer to be bitten by mosquitoes."

In the worker's paradise, not all so-called enemies of the state were incarcerated or sent to labor camps. Some were forcibly removed from their homes and exiled to regions of the country hostile to human survival. In Cambodia, for instance, entire cities were emptied in a reverse urbanization project meant to create wholesome peasant stock. A similar Chinese operation was both punitive and remedial, counting on the salutary effects of field labor upon insufficiently docile white-collar bureaucrats.

Communists directed all relocations; any unapproved change of domicile, even across town, was dangerous. Across borders, it usually proved lethal. "Flight abroad or refusal to return from abroad" was listed, alongside "treason and espionage", as an "especially dangerous crime against the state", not only in the Soviet Union but also in its clones. Communist states sought to protect themselves from their own citizens.

One of the most bizarre common "judicial proceedings" was the use of tortured or blackmailed "confessions" as solid proof. In Cambodia, political guilt was established entirely by confession. In Albania, interrogators used tapes of detainees' families "pretending they had all been arrested and tortured", which predictably extracted the requested statements.

Deciding what to include in this volume had to be an excruciating task. Solzhenitsyn was an obvious choice, but excerpting One Day in the Life of Ivan Denisovich, rather than The Gulag Archipelago, perhaps less so. Vladimir Bukovsky's To Build a Castle, like Anatoly Marchenko's My Testimony, are self-evident, but arguably so are Natan Sharansky's titanic story Fear No Evil and the works of Nadejda Mandelstam, Valery Chalidze, Victor Herman and dozens of other Soviet dissidents.

The inevitable incompleteness in the Soviet realm, however, is more than compensated for by attention paid to smaller nations. In Cambodia-where torture and cruelty were "more widespread than in any other Communist regime"-"shooting was not the most common means of execution . . . only 29% of the victims died that way." A less fortunate 53 percent "died from blows to the head, inflicted with iron bars, pick-up handles or agricultural implements; 6% were hanged or asphyxiated with plastic bags; and 5% had their throats slit." Cambodians needed to economize on bullets and perhaps relieve some utopia-building stress.

Good old starvation was less messy, and all these countries excelled in it. One remarkable witness is Vietnam's Doan Van Toai, who had been a student leader and critic of the anti-communist government before 1975. The Communists arrested him soon after coming to power in an apparent case of mistaken identity. He spent three years in prison and a prison camp, an experience recounted in The Vietnamese Gulag.

A question haunts the reader through each excruciating page: Who is capable of such massive and systematic sadism? Hollander identifies three main types. At the top are the "ideologically driven, puritanical, and ruthless individuals", such as directors of the KGB, notably Felix Dzerzhinsky, who "seemed immune to doubt, inner conflict, and reservations about the use of harsh, even murderous methods." These specimens are usually found early in the life of the regime, when the bankruptcy of communist pseudo-economics and the ubiquitous hypocrisy is less manifest.

Next in line is the bureaucrat, the yes-man, the follower of orders. A prime example is Kang Kek Ieu, head of the Khmer Rouge Secret Police and commandant of a prison where 14,000 people were tortured and killed. He "sought to make clear" he didn't enjoy his job; indeed, he was "constantly concerned about the quality of his product." One wonders what he thought that product was.

The third breed consists of "amoral or unmistakably malevolent individuals." These sinister creatures are disproportionately represented in the "security forces"-their satanic handicap, in fact, is a job requirement. Yet Hollander notes that "Western social scientists, while readily ascribing certain pathologies to leading Nazis, have resisted recognizing similar traits among Communist leaders, functionaries, or heads of police."

This is the subject of Hollander's other remarkable new book, The End of Commitment, which explores the heinous crimes' effects on those who originally defended communism. It is a study of ideological disillusion-as valuable as it is rare, given how political "science", especially in the United States, seeks to mimic the relative precision that characterizes physics and even neurobiology. Imprecisely dubbed as "sociology of knowledge", Hollander's approach is explicitly based on his wholehearted agreement with philosopher Isaiah Berlin that "the wishes and purposes of identifiable individuals" are critical for understanding human behavior and historical events. This is a minority opinion in the American academy, both left and (to the extent that it survives) right.

While he certainly does not discount macro, impersonal forces like economics and geography, Hollander focuses on the political beliefs of revolutionary leaders who, for better or (more often) worse, clearly change history. And while most of his research involves communist renegades, his approach is particularly relevant in the war against Muslim fanatics. Writes Hollander: "the Islamic terrorists of our time exemplify a watertight, overdetermined connection between belief and behavior, or idealism and behavior", whose resemblance to their Marxist predecessors in ideological commitment is uncanny.

To be sure, the study mirrors an important limitation of the anthology, namely its inclusion of only prominent ex-true believers. But the resulting over-representation of intellectuals is by no means accidental. A proclivity for absolutes, a lack of worldliness and often unabashed arrogance are virtually occupational qualifications, if not outright prerequisites, of the chattering and scribbling classes. Richard Posner adds one more, especially dangerous, trait: "selective empathy, a selective sense of justice, and insensitivity to context." A pure specimen is MIT professor Noam Chomsky, but there are many others, no less noxious, if less strident.

Like Hollander's anthology, this other study scans the globe. First in line is, of course, the Soviet Union and Eastern Europe, which produced the best-known communist-era defectors. They include former members of the nomenklatura like secret police official Alexander Orlov and United Nations Secretariat official Arkady Shevchenko, but also literary scholars like Lev Kopelev. Less well known are Hungarian ex-Prime Minister Andras Hegedus, journalist Miklos Gimes and former Czech Public Prosecutor Zdenek Mlynar.

American Sidney Rittenberg is mentioned in the section on China, not so much for having spent 35 years in that country, 16 of them in prison (notwithstanding his devotion and loyalty to its government), but for the aftermath. Having settled in the United States with his Chinese family in 1977, after release from his second imprisonment, with no sign of bitterness, Rittenberg founded a lucrative consulting business promoting American trade with China. According to The New York Times, Rittenberg was thus typical of many others from the PRC: "Like the Chinese officials who were once his junior comrades, [he] does not seem to waste much time wrestling with his conscience over his new role helping those who in the past he might have described as imperialist forces" bent on destroying China's valiant experiment.

In this respect, however, he differs from most of the victims of communism, whose disenchantment was usually personally shattering. Inside those regimes, it often led to torture, imprisonment and usually death, not only for themselves but also for family members and friends. In the West, such disillusion usually brought ostracism, which could mean loss of academic jobs, bad reviews and the silence of contempt. Actually, it is the phenomenon of Western leftists' reactions to realities behind the Red Curtain that has interested Hollander for most of his career, and on which he focuses most extensively in The End of Commitment.

Biographies of author Howard Fast, Hollywood critic David Horowitz, politics professor Ron Radosh and historian Eugene Genovese are followed by those of British novelist Doris Lessing and former compatriot journalist Christopher Hitchens, as well as Jewish-American student of Latin America Maurice Halperin. An especially detailed section is devoted to author Susan Sontag, who arguably might have fit better in the next chapter entitled "Disaffection and Resisting It." That chapter ends as follows: "A wounded idealism seeking an outlet in leftist social or political activism appeared to be the most widely shared trait" by the resistant disaffected. As to the source of that idealism, and how it could be channeled in ways less harmful to the United States-these questions are well worth additional study.

There are countless more questions and topics that beg further exploration. In this sense, Hollander's two new books can be described as thoroughly tantalizing. The serious reader will want a deeper understanding of how otherwise intelligent human beings become mesmerized by utopian thinking. The hope is for a global effort to gain such understanding, especially given the treasure of archival documents Russia and its former satellites recently released. Objective, devoted scholarship in this area is critical, if for no other reason than to learn how to approach the threats of our own generation. We must achieve more sophisticated insights into the catastrophic effects of self-righteous fanaticism and the dystopias that invariably follow.